.stack {
  margin: 20px auto;
  width: 400px;
  padding: 0;
  position: relative;
  max-width: 100%;
}
.stack img {
  max-width: 100%;
  position: absolute;
  top: 0;
  left: 0;
  -webkit-transition: all 0.3s;
  -moz-transition: all 0.3s;
  -o-transition: all 0.3s;
  transition: all 0.3s;
  outline: 1px solid transparent;
  box-shadow: 0 0 30px rgba(0, 0, 0, 0.1);
  -webkit-box-shadow: 0 0 30px rgba(0, 0, 0, 0.1);
  -moz-box-shadow: 0 0 30px rgba(0, 0, 0, 0.1);
  -o-box-shadow: 0 0 30px rgba(0, 0, 0, 0.1);
}
.stack img:last-child {
  position: relative;
}
.stack-sideslide img:first-child,
.stack-sideslide img:nth-child(2) {
  visibility: hidden;
  opacity: 0;
  -webkit-transition: -webkit-transform 0.3s, opacity 0.3s, visibility 0s 0.3s;
  -moz-transition: -moz-transform 0.3s, opacity 0.3s, visibility 0s 0.3s;
  -o-transition: -o-transform 0.3s, opacity 0.3s, visibility 0s 0.3s;
  transition: transform 0.3s, opacity 0.3s, visibility 0s 0.3s;
}
.stack-sideslide img:first-child {
  -webkit-transform: translateX(-50%) scale(0.5);
  -moz-transform: translateX(-50%) scale(0.5);
  -o-transform: translateX(-50%) scale(0.5);
  transform: translateX(-50%) scale(0.5);
}
.stack-sideslide img:nth-child(2) {
  -webkit-transform: translateX(50%) scale(0.5);
  -moz-transform: translateX(50%) scale(0.5);
  -o-transform: translateX(50%) scale(0.5);
  transform: translateX(50%) scale(0.5);
}
.stack-sideslide.active img:nth-child(3) {
  -webkit-transform: scale(0.8);
  -moz-transform: scale(0.8);
  -o-transform: scale(0.8);
  transform: scale(0.8);
}
.stack-sideslide.active img:first-child,
.stack-sideslide.active img:nth-child(2) {
  opacity: 1;
  visibility: visible;
  -webkit-transition: -webkit-transform 0.5s, opacity 0.5s;
  -moz-transition: -moz-transform 0.5s, opacity 0.5s;
  -o-transition: -o-transform 0.5s, opacity 0.5s;
  transition: transform 0.5s, opacity 0.5s;
}
.stack-sideslide.active img:first-child {
  -webkit-transform: translateX(-30%) scale(0.7);
  -moz-transform: translateX(-30%) scale(0.7);
  -o-transform: translateX(-30%) scale(0.7);
  transform: translateX(-30%) scale(0.7);
}
.stack-sideslide.active img:nth-child(2) {
  -webkit-transform: translateX(30%) scale(0.7);
  -moz-transform: translateX(30%) scale(0.7);
  -o-transform: translateX(30%) scale(0.7);
  transform: translateX(30%) scale(0.7);
}